Stable band consisting of sized staple fibers and possessing high lengthwise stability

ABSTRACT

A STABLE BAND POSSESSING HIGH LENGTHWISE STABILITY WHEREIN THE ELASTIC ELONGATION OF THE STABLE BAND, COMPARED TO ONE IN WHICH BINDING OCCURED IN A TENSION-FREE STATE, IS SEVERAL TIMES SMALLER.

' 2 Sheets-Sheet 1 v WISE STABILITY w. NAEGELI.

AND POSSESSING HIGH LENGTH Filed larch 13, 19 '7- 0 oiskm'ssioil Sept.24, 1914 Original Fig. 8

STABLE BAND-GONSISTING OF SIZED STAPLELFIBERS w. NAEGELI 3,837,998

AND POSSES SING HIGH LENGTHWISE STABILITY.

Original Filed larch 13, 1970 United States Patent US. (:1. 161-170 2Claims ABSTRACT OF THE DISCLOSURE A stable band possessing highlengthwise stability wherein the elastic elongation of the stable band,compared to one in which binding occurred in a tension-free state, isseveral times smaller.

CROSS-REFERENCE TO RELATED CASE The present application is a divisionalapplication of my commonly assigned, co-pending US. application, Ser.No. 19,243, filed Mar. 13, 1970, and entitled Method of Producing aStable Band Consisting of Sized Staple Fibers of High LengthwiseStability and Stable Band Produced According to the Aforesaid Method,"now Pat. No. 3,770,538.

BACKGROUND OF THE INVENTION The present invention concerns a new andimproved stable band consisting of adhesively interconnected staplefibers and possessing high lengthwise or longitudinal stability.

In spinning processes it is already known to produce stable bandsconsisting of staple fibers by means of treating or impregnating asuitably prepared untwisted strand of staple fibers with an excess ofadhesive distributed in a liquid, with the surplus liquid being squeezedoff and the fibers mutually compressed in a pressure zone. Further, thestaple fibers are compressed into a compact band and by dryingtransformed into a stable band possessing sufficient lengthwisestabilization for undergoing a drafting operation. As a measure forjudging the lengthwise stabilization the slope of the force-elongationcurve of a band is chosen. Such stabilized bands exhibit that muchbetter drafting properties for a subsequent drafting operation in adrafting arrangement, the higher the lengthwise stabilization of thestable bands is chosen. Since the average drafting force exerted upon astable band subjected to a drafting operation is not constant, the bandgripped in the nip of the drafting rolls of a drafting arrangement issubject to varying elongation, which, if a certain value is exceeded,can cause drafting waves. By producing suificiently lengthwisestabilized stable bands it is largely possible to eliminate these feareddrafting waves which occur during drafting of normal twisted rovings andto produce yarns of good uniformity.

SUM-MARY OF THE INVENTION Accordingly, it is a primary object of thepresent invention to improve the elastic properties of a stable band inthe drafting arrangement by a further degree or steps by means of afurther increase of the lengthwise stabilization, that is, byconsiderably increasing the slope of the force-elongation curve in theforce-elongation diagram in order to reduce the elongation of the band,when subjected to a certain average drafting force, to such an extentthat it becomes negligibly small and no longer can influence thedrafting operation. In this manner production of very even yarns can beachieved.

3,837,998 Patented Sept. 24, 1974 A further object of the presentinvention is to be seen in substantially maintaining the band structureestablished by compressing in the wet state during the subsequenttreatment until the adhesive binds, and in effectively stabilizing theband in this compressed shape, which is of particular importance inprocessing fibers showing marked bulking tendency.

Now, in order to achieve these and still further objects of theinvention, which will become more readily apparent as the descriptionproceeds, the invention contemplates forming a stable band composed ofadhesively interconnected staple fibers of high lengthwise stability bymeans of treating with an excess of liquid in which an adhesive isdistributed, then squeezing off the liquid surplus, and compressing thefibers by applying pressure into a compact band in which the adhesivebinds, and by application of tensile force the band is subjected to anelongation within the limits of elastic deformation while binding of theadhesive takes place.

A further aspect of the invention is characterized in that, the bandafter being compacted or compressed and before binding of the adhesivetakes place, is subjected to an elongation within the limits of elasticdeformation.

Furthermore, binding of the adhesive induced by drying can be effectedat the highest possible temperature.

The stable band of high lengthwise stability produced according to theinventive method is manifested by the features that its elasticelongation is several times smaller than a fiber band in which bindingof the adhesive occurred in a tension-free state.

BRIEF DESCRIPTION OF THE DRAWINGS tion of the continuous process fortreating staple fiber bands.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Describing now theinvention, a staple fiber band produced by a suitable preparatorymachine, e.g. by a card, is treated in a known manner with an excess ofliquid in which an adhesive is distributed. By squeezing off the liquidsurplus and compressing the band there results a compact, smooth butstill wet staple fiber band containing a certain amount of adhesive, thebonding or binding of which has not yet taken place. This band alreadyexhibits elastic properties under tension, that is, such band can betensioned closely up to its wet breaking strength without sufieringpermanent deformation. Such bands are now elongated within the limits ofelastic deformation before, or at the beginning of, the bonding orbinding of the adhesive by means of applying tension which is below theWet breaking strength of said bands. This tension may be kept constantduring the bonding process or may be varied within the limits of elasticdeformation according to certain parameters or functions, for example,in order to take into account the changing length of the fibers duringbinding of the adhesive. The band also may be elongated by tens-ionbefore binding takes place and its length may be maintained constantwhile binding occurs, in which case the elongation is subject to changesaccording to the magnitude of the tension generated by the shrinkagewhich develops. Care must be taken in this case, however, that the bandin its wet, partially or fully bonded state, is not over-elongated whichwould cause band breakage.

The inventive method can be carried out in a discontinuous process aswell as in a continuous process. In discontinuous processing certainlengths of condensed, wet bands are laid out or suspended intension-free state and then are tensioned by elastically elongating to acertain degree, and in this state are subject to a binding process.Binding of the adhesive, as a rule, is induced by extraction of theliquid, e.g. a solvent, most simply merely by drying. Binding, however,may be also induced by radiation, ionization or through the action ofsuitable gases, depending upon the adhesive used.

More explicitly, the discontinuous processing technique is describedwith reference to the following Examples I to III in which the band istensioned to a certain degree before binding takes place, short bandlengths being chosen solely for measuring purposes, from which bandlengths short lengths of yarn only could be spun. In practice, a lengthcorresponding to at least a usual package creeled on a ring spinningframe would have to be chosen. In the following Example binding isinduced by drying, that is, extraction of the solvent by evaporation.

Example I A carded cotton of (American province) K.S. origin, of 1staple length suitably prepared in a preparatory process, in a bandweight of 1972 tex, is fed into a liquid applicator device, e.g. asdescribed in Swiss Pat. 426,704 and is removed in the form of acompressed or compacted band. As treatment liquid there is used 7%aqueous solution of the commercially available starch derivative productNoredux 100, marketed by the Swiss firm, Blattmann & Co., of Wadenswil,Switzerland. A wet band of 1 meter length is cut from the band deliveredby the liquid applicator device and is freely laid out horizontally.Drying took place without influence of any tension during 3 minutes at aconstant temperature of about 80 C. In the dry state the band wasclamped in a Tensile-Tester of the Instrom Company, Ltd., High Wycombe,Bucks, England, and the force-elongation diagram marked a in FIG. 1 wasrecorded. Another band prepared in the same manner was clamped in itswet state, a free length of 1 meter being maintained, and was elongatedby 0.5%, which corresponds to an elastic deformation of the wet band of5 mm. Subsequently, drying took place again during 3 minutes at constantlength and at a temperature of 80 C. The force-elongation diagram asshown by curve b was recorded. In the same manner, a further wet band of1 meter length was processed, elongation being increased to 1 percent.The force-elongation diagram obtained from this band is shown by curve0. The resulting elongation percentages at a load force B=4 kg. aregiven in the following table:

Percent elonga- Percent tion elongaapplied tion in the of the wet;stable Curve state band 1 1 After binding, under load force B =4 kg.

Comparison of the elongation of the bands dried without tension and ofthe bands dried under tension shows a ratio of about 1:2 or better.

Example II firm, Polygal Co., Meerstetten, Switzerland. A 1 meter lengthof band was dried without tension at C. and its force-elongation curve ashown in FIG. 2 was recorded on the Instron Tensile Tester. Anotherpiece of the same band was clamped in its wet state maintaining a freelength of 1 meter and was elongated by 2% and was dried at 80 C. during3 minutes. The resulting force-elongation diagram is shown in curve b.Similarly, a 1 meter length of the same band was elongated by 4%,clamped and dried, curve 0 resulting from this test. The elongationpercentages as shown in the diagram, at a load force of 10 kg., aregiven in the following table:

Percent elonga- Percent tion elongaapplied tion in the of the wet stablestate band 1 1 After binding, under load force B =10 kg.

Example III A 1972 tex band of highly crimped acrylic fibers of 53 mm.cutting length was fed into a liquid applicator device and was taken offas a compacted or compressed band. The treatment liquid was a 50%aqueous solution of the polyacrylate BAS-TX of the well known firmBadische Anilinund Sodafabriken, Ludwigshafen, Germany. Again, 3 bandpieces each of 1 meter length were cut and dried at 80 C. during 3 min.with,

one being laid out without tension,

the second being pre-elongated by 2%, and

the third being pre-elongated by 5% and clamped, maintaining 1 meterclamping distance, and dried at 80 C. for 3 minutes.

The corresponding force-elongation diagrams are shown in FIG. 3. At aload force of 13:10 kg., the following elongation percentages are found:

Percent elonga- Percent tion elongation of the applied in stable Curvethe wet state band 1 0 (tensionless) 12 Alter binding, under load forceB =10 kg.

Thus, the elongation is 3.5 to 5.5 times smaller, which permits aconsiderable improvement of the lengthwise stabilization, and thus alsoof the draftability of highly crimped fibers.

From these examples it is evident that for an average drafting force, towhich such bands are subject in the drafting zone, the elongationproperties can be improved so decisively that the changes in lengthunder the influence of the average drafting force, and thus of thenumbers of fibers gripped in the nip of the front rolls, remainspractically constant at each moment, resulting in excellent yarnuniformity. The discontinuous processing technique alternatively can beused by applying tensile load to the wet, condensed bands before andduring the binding phase by exposing the bands to a constant tensileload causing Example IV A band as described in Example I is treated witha 5.5% solution of the cellulose derivative Solvitose X0 and SolvitoseX1 (manufactured by Scholtens, Chemische Fabriken, Foxhal/Holland) mixedin the proportions 1 to 4, and is removed in the form of a compacted orcompressed band; Wet bands of 80 cm. length are clamped at their upperend, suspended vertically, and are weighted at their lower end withweights of (for straightening only by slight tension), 150 and 300 gramsrespectively. Each band is dried in an air convector box for 8 minutesat 80 C. under the influence of the weights mentioned, and subsequentlythe force-elongation diagram is recorded on the Instron Tester. Theresulting curves are shown in FIG. 4. The elongation percentages under aload force of B=4 kg. are given in the following table:

Percent Weight elon gaload tion in grams of the applied dried in thestable Curve wet state band 1 Under load force B=4 kg.

Example V A 1972 tex band of 1.5 den. Terylene fibers of 38 mm. cuttinglength was treated with liquid and taken off as a compressed band in thesame manner as described in the preceding Examples. The treatment liquidused was a 30% aqueous solution of Vibatex S, a polyvinyl alcoholmanufactured by Ciba Corp., Basel, Switzerland. During the 8 minutedrying process at 80 C. the bands of 80 cm. length again were loadedwith weights of 10', 150, 300, 450 and 600 grams respectively. Theforce-elongation diagrams shown in FIG. 5 resulting from the bands driedunder the weight loads mentioned above, depict the elongationpercentages at a certain load force given in the following table:

1 Under load force B=4 kg.

From this it is evident that already using relatively mod erate bandtensioning, elongation can be lowered substan tially, i.e. that thedrafting behavior of the bands can be improved considerably.

The lengthwise stabilization of the bands can be improved further in thecase of binding, induced by supplying heat, i.e. drying, by using highertemperatures, as it was found that otherwise equally processed bandsdried at higher temperatures show smaller elongation. The results showthe same trend, no matter whether the bands are tensioned in the wetstate and clamped, or whether they are loaded at their free end. Thepreceding Example V and the following Examples VI to VIII give a moredetailed illustration.

Example VI The same example as in Example V was carried out, the onlydifference being that drying in the air convector box was carried out ata temperature of C. The force-elongation diagrams obtained from suchbands are shown inFIG. 6. At a load force B=4 kg. the elongationpercentage summarized in the following table are found:

Percent Weight elongaload tion in grams of the applied dried in thestable Curve wet state band 1 1 Under load force B=4 kg.

From these results it is evident that using the same band tensions at ahigher drying temperature, a reduction of elongation can be achieved,which again results in improved lengthwise stabilization of the bandwhich is favorable if the band is subsequently drafted.

Example VII Bands prepared as in Examples V and VI of 80 cm. length wereelongated in the wet state by O, 1, 1.5, 2 and 2.5 percent respectively,and in this state were clamped at both ends. Drying then was effected at80 C. The corresponding elongation percentages at a load force B=4 kg,as shown by the force-elongation diagrams of FIG. 7 recorded on theInstron Tester, are reduced according to the following table:

Percent Percent elonelongation gation of the applied in dried the wetstable state band 1 1 Under load force B =4 kg.

Here also a marked reduction in elongation percentages is noticed at thehighest tension during drying.

Example VIII Percent Percent elonelongation gation of the applied indried the wet stable state band 1 1 Under load force B =4 kg.

Comparison with the results of Example VII shows a further markedreduction in elongation percentages of the dried bands.

If the method is used in continuous manner, processing is effected asfollows:

A compressed or compacted band 2 of staple fibers emerges from anapplicator device 1 (FIG. 9) at the speed V and is transferred at thepoint A at a speed V =V helically onto a rotating drum 4 arranged in ahousing 3 where it is subjected to a process inducing bonding of theadhesive. At point B, at the other end of drum 4, the band containingfiber mutually interconnected by the bound adhesive, now called stableband, leaves drum 4 and after passing through a traversing band guide iswound onto a band package 6. Binding of the adhesive occurs in theprocessing zone between the points A and B under a tension within thelimits of band elasticity generated and maintained up to the departurepoint B. This tension can be adapted to requirements by choosingsuitable diameter ratios of drum 4 insofar as the magnitude of theshrinkage of the stable band, depending upon a number of factors, suchas type of fibers, temperature, duration of processing etc., must betaken into account. If, as in FIG. 9, a drum of constant diameter D=D ischosen, drying is effected while band length is maintained constant,i.e. the band is elongated elastically by the same amount as it shrinksduring processing. If the drum diameter is reduced by means of choosinga slightly tapered drum shape (drum shown in dashed lines D D)elongation of the band on the drum is reduced. Diameter D however,should not be chosen so small that tension drops to zero. In analogy,diameter D of drum 4 can be increased (drum shown in dash-dotted lines,D D so that the band tension is increased somewhat. Diameter D should,however, not be increased so much that the limit of elastic elongationof the band is exceeded.

Using this method, continuous processing is achieved as opposed to themethod used in the preceding examples, where processing wasdiscontinuous. Transfer of the band to the subsequent winding device maybe effected tensionfree or under tension, the band now being stabilizedand its structure no longer being altered under the influence oftension, i.e. tension between the processing zone and the winding devicemay be chosen according to winding requirements.

In the continuous processing method there is the further possibility ofchoosing the circumferential speed V of drum 4 at point A higher than Vso that also between said drum 4 and the liquid applicator devicetensioning within the limits of elastic band elongation is effected. Inthis manner the compressed band 2 can not widen free of tension beforereaching drum 4. The fibers also can not contract lengthwise due totheir inherent crimp, nor effect mutual relative movements. Elongationthus will be chosen at least so large that fiber crimp straightened outby compressing cannot re-develop.

As a further alternative a method of continuous processing can be chosenin which the compressed band 7 (FIG. treated or impregnated with anadhesive distributed in a liquid is guided directly through a processingzone 8 and subsequently is wound onto a package 9. In the processingzone 8 the liquid is extracted. In this case the winding speed V inrelation to the delivery speed V is chosen such, that the tension in theband 7, not yet stabilized, remains within the limits of elasticelongation in the processing zone 8 in spite of the fiber shrinkage.

The method makes use of the elastic deformation properties of the bandsinsofar as the band after the described treatment with liquid andcompressing can be subject to tension without suffering a permanentchange in length. In this manner the inherent fiber crimp cannot reversethe previously established band compression and binding occurs in thecompressed state of the band.

While there is shown and described present preferred embodiments of theinvention, it is to be distinctly understood that the invention is notlimited thereto but may be otherwise variously embodied and practicedwithin the scope of the following claims.

Accordingly, what is claimed is:

1. A stable band composed of an untwisted arrangement of adhesivelyinterconnected staple fibers and having high lengthwise stability, saidstable band being stabilized by the staple fibers compressed into acompact untwisted band and bonded by a set adhesive material remainingin the band following compression, said stable band comprising saidcompact band having been elongated in its wet state within the limits ofelastic deformation by application of a tension force while binding ofthe adhesive took place, and said stable band possessing an elasticelongation which, compared to a same stable band in which bindingoccurred in a tension-free state, is several times smaller.

2. A stable band composed of an untwisted arrangement of adhesivelyinterconnected staple fibers and having an increased slope of theforce-elongation curve in the force-elongation diagram, said stable bandbeing stabilized by the staple fibers compressed into a compact band andbonded by a set adhesive material remaining in the band followingcompression, said stable band comprising said compact band having beenelongated in its wet state within the limits of elastic deformation byapplication of a tension force following compression of the staplefibers into said compact band and while binding of the adhesive tookplace, said stable band possessing a force-elongation curve in theforce-elongation diagram wherein'the slope thereof, compared to a samestable band in which binding occurred in a tension-free state, isincreased, and said stable band being capable of being drafted.

References Cited UNITED STATES PATENTS 2,454,830 11/1948 Newton 1611762,461,094 2/1949 Taylor 156229 X 1,803,129 4/1931 Palmer 1l77 X2,977,665 4/1961 McElrath 1177 X WILLIAM A. POWELL, Primary Examiner US.Cl. X,R. 616 2 494

